Patent GB-867483-A (GB)
Title: Improvements in or relating to the manufacture of oil-soluble petroleum sulphonic acids
IPC: F02B75/02
Filed: 1958-05-02
Abstract: Oil-soluble sulphonic acids are produced by dehydrogenating a naphthene-containing petroleum oil, such as a refined lubricating oil boiling in the range of 300 DEG -500 DEG C., in the presence of a catalyst comprising a noble metal of Group VIII of the Periodic Table, whereby the naphthene components in the oil are converted into aromatic hydrocarbons, and subjecting the aromatized oil to sulphonation.  If the lubricating oil contains an appreciable proportion of olefins, mercaptans or nitrogen compounds, it is preferably subjected to a hydrogenation-pretreatment.  Resinous and coloured impurities may be removed by passing the oil through a bed of adsorbent clay or charcoal at temperatures of from 100 DEG  to 350 DEG C.  Aromatics may be removed from the oil, prior to the aromatization process, by solvent extraction with sulphur dioxide, treatment with silica gel, or presulphonation.  The aromatization of the refined oil is preferably carried out at atmospheric pressure, at a temperature between 300 DEG  and 400 DEG C., and in the presence of a platinum, palladium, rhodium or iridium catalyst supported on alumina, silica, magnesia, charcoal or graphite. The catalyst should preferably contain combined chlorine or fluorine; or it may contain other acid-acting components such as aluminium silicate, chloride or oxychloride or hydrochloric, hydrofluoric, sulphuric or phosphoric acid.  The sulphonation of the aromatized oil may be carried out with concentrated sulphuric acid, oleum, liquid sulphur trioxide, chlorosulphonic acid, or fluorosulphonic acid.  The sulphonating agent may be mixed with liquid sulphur dioxide, propane, n-butane, dichlorodifluoromethane or other volatile liquid which boils at the desired sulphonation-temperature.  When utilizing oleum or liquid sulphur trioxide, the sulphonation may be carried out at temperatures in the range of -30 DEG  to +60 DEG C., utilizing molar ratios of free SO3 to aromatic component in the lube oil feed stock of from 1 to 1 up to about 2 to 1.  After separation of excess sulphonating-agent from the oil, the sulphonic acids, dissolved in the oil, may be neutralized with a suitable neutralizing-agent selected from aqueous solutions of the oxides, hydroxides and carbonates of sodium, lithium, potassium, calcium, magnesium or barium.  The hydroxide of a weak acid salt of aluminium may also be used.  In Examples 1, 2 and 3, the sulphonated product is neutralised by adding aqueous caustic soda and iso-propanol, whereby three liquid layers are formed.  The aqueous alcohol layer is separated, and evaporated to yield pure sodium alkylaryl sulphonates.  In Example 4, the neutral oil residue, separated at the decantation stage, is treated with 20% oleum in two cycles, each of two stages, with neutralization at the end of each cycle. The treated oil is then contacted with activated bleaching clay at 70 DEG C.  The oil is finally filtered to give a medicinal liquid paraffin of British Pharmacopoeia quality except in respect of viscosity.  Example 5 relates to the preparation of a lubricating oil composition (see Group III).  Specification 657,565 is referred to.ALSO:A lubricating oil containing a metal alkylaryl sulphonate is produced by dehydrogenating a petroleum lubricating oil stock, containing napthene hydrocarbons, at a temperature of 300 DEG  to 450 DEG C. in the presence of a catalyst containing 0.01 to 3% by weight of platinum and 0.01 to 3% by weight of combined halogen supported on alumina, subjecting the aromatized oil to sulphonation, and then neutralizing the sulphonated oil with a metallic oxide, hydroxide or carbonate.  If the lubricating oil stock contains an appreciable proportion of olefins, mercaptans or nitrogen compounds, it is preferably subjected to hydrogenation-pretreatment.  Resinous and coloured impurities may be removed by passing the oil through a bed of adsorbent clay or charcoal at temperatures of from 100 DEG  to 350 DEG C.  Aromatics may be removed from the oil, prior to the dehydrogenation process, by solvent extraction with sulphur dioxide, treatment with silica gel, or pre-sulphonation.  The sulphonation of the dehydrogenated oil may be carried out with the usual sulphonating reagents (see Group IV(b)).  In Example 5, the sulphonated oil is neutralized with an aqueous solution of lithium hydroxide; and the neutralized oil is mixed with a paraffin base oil, from which naphthenes have been removed, to give a detergent oil composition containing approximately 1.5% by weight of lithium sulphonates.  This oil is in an effective lubricant in an engine crankcase.  The example also describes a composition wherein the lithium sulphonates, obtained as above, are mixed with lithium sulphonates derived from sulphonic acids obtained by pre-sulphonation of the raw oil stock, i.e. prior to dehydrogenation thereof.  Specification 657,565 is referred to.